Today so-called “smart power devices” are increasingly used. A smart power device, in some applications also called “intelligent power switch” (IPS) or “intelligent power module” (IPM) usually includes power electronics for controlling the power supply of an electric or electronic load as well as additional circuitry which are used for monitoring and/or controlling the operation of the load, which may include protecting the load against overload or overtemperature conditions. As all those devices (smart power devices, IPM, IPS and similar) are used to drive at least one electric load such devices are generally referred to as load drivers as load driver circuits. In this context the term electric loads includes any device which needs an power (voltage and current) supply to be operated, including electromechanical devices (such as electric motors), electrochemical devices such as a battery as well as ohmic, inductive or capacitive loads (or a combination thereof).
As mentioned load driver circuits may include circuitry for controlling the power supply (load current and operating voltage) provided to a load. In a simple example such circuitry for controlling the power supply includes a single transistor such as a MOSFET. However, more sophisticated circuitry may be used such as transistor half-bridges or transistor H-bridges. Furthermore, a load driver circuit may include further a measurement circuit, which may be used to measure one or more operation parameters of the load such as load current, maximum load current, average load current, switching frequency, operation voltage, temperature or any other desired operation parameter of the load or of the driver circuit itself. The load driver circuit may also include a control circuit which may be, for example, configured to perform general control functions such as rotation speed control in case the load is an electric motor or the control of a battery charging process (e.g. of a lithium-ion battery cell of an electric or hybrid-electric vehicle). In many applications these control functions include protection functions such as over-voltage or over-temperature protection or other security relevant functions. In the mentioned example, in which the load is a rechargeable battery, these control functions are typically included in a so-called battery management system.
The performance of the mentioned control functions may depend on device specific parameters of the load such as thresholds for current limitation, armature circuit resistance in case of an electric motor, internal resistance of a battery being charged, etc. However, these device-specific parameters of the load are a priori unknown and thus the smart power device, which includes the load driver circuit, is usually designed for a broad range of different products, which might be operated using the smart power device. Furthermore, at least some device-specific parameters of the load may change over time due to aging effects. As a result, optimization with regard of the operation of a specific electric device used as load is not readily feasible.